HC05 datasheet(139/232 Pages) MOTOROLA

139 / 232 page

MC68HC05X16

Rev. 1

MOTOROLA

10-5

RESETS AND INTERRUPTS

10.1.4.1

COP watchdog during STOP mode

The STOP instruction is inhibited when the watchdog system is enabled. If a STOP instruction is

executed while the watchdog system is enabled, then a watchdog reset will occur as if there were

a watchdog timeout. In the case of a watchdog reset due to a STOP instruction, the oscillator will

not be affected, thus there will be no tPORL cycles start-up delay. On start-up, the watchdog will be

conﬁgured according to the user speciﬁed mask option.

10.1.4.2

COP watchdog during WAIT mode

The state of the watchdog during WAIT mode is selected via a mask option (see Section 1.2) to

be one of the options below:

Watchdog enabled — the watchdog counter will continue to operate during WAIT mode and a reset

will occur after time tDOG.

Watchdog disabled — on entering WAIT mode, the watchdog counter system is reset and

disabled. On exiting WAIT mode the counter resumes normal operation.

10.1.5

Functions affected by reset

When processing stops within the MCU for any reason, i.e. power-on reset, external reset or the

execution of a STOP or WAIT instruction, various internal functions of the MCU are affected.

Table 10-1 shows the resulting action of any type of system reset, but not necessarily in the order

in which they occur.

Note:

Reset action on individual MCAN registers is described in Section 5 and is also

summarised in Table 3-2.

137

HC05 Datasheet(PDF) 139 Page - Motorola, Inc